BCEM 393 Lecture Notes - Lecture 2: Bovine Serum Albumin, Mercedes-Benz E-Class, Lysine

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rosefrog223

1 Jun 2018

School

University of Calgary

Department

Biochemistry

Course

BCEM 393

Professor

Robert Allan Edwards

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Lab Lecture 1

PEPTIDE BOND

- Dehydration forms peptide bonds (amide) to link amino acids together

- The alpha amino and alpha carboxyl groups are destroyed

- Dehydration requires energy (from GTP) in the cell

- The equilibrium lies on the side of hydrolysis, but peptide bonds are kinetically stable

POLYPEPTIDE (>10 RESIDUES)

- Backbond of the polypeptide is: -N-Calpha-C-N-Calpha-C-

- Side chains (green) alternate in stereochemistry

- The chain has directionality, and is written from the amino terminal (N-terminus) to the

carboxyl terminal (C-terminus)

PROTEINS

- A protein is a (usually folded) polypeptide composed of more than or equal to 50 amino acid

residues

- The average weight for an amino acid residue is 115 g/mol, therefore, a protein with 50 amino

acid residues has a molecular weight of approximately 5750 g/mol

- Primary structure is the linear sequence of amino acids (residues) polymer formed by linking

amino acid residues with peptide bonds for a particular protein

- Written from N-terminus to C-terminus

AMINO ACID SEQUENCE OF BOVINE INSULIN SHOWING DISULFIDE BONDS

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Document Summary

Dehydration forms peptide bonds (amide) to link amino acids together. The alpha amino and alpha carboxyl groups are destroyed. Dehydration requires energy (from gtp) in the cell. The equilibrium lies on the side of hydrolysis, but peptide bonds are kinetically stable. The chain has directionality, and is written from the amino terminal (n-terminus) to the carboxyl terminal (c-terminus) A protein is a (usually folded) polypeptide composed of more than or equal to 50 amino acid residues. The average weight for an amino acid residue is 115 g/mol, therefore, a protein with 50 amino acid residues has a molecular weight of approximately 5750 g/mol. Primary structure is the linear sequence of amino acids (residues) polymer formed by linking amino acid residues with peptide bonds for a particular protein. Amino acid sequence of bovine insulin showing disulfide bonds. Cys 7 of the a chain is linked to the cys 7 of the b chain.

Related Questions

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below. Not all words or phrases will be used; each word or phrase should be used only once. Proteins are ______________ built from amino acids, which each have an amino group and a _____________ group attached to the central _______________. There are twenty possible _______________ that differ in structure and are generally referred to as âR.â In solutions of neutral pH, amino acids are _______________, carrying both a positive and negative charge. When a protein is made, amino acids are linked together through _______________, which are formed by condensation reactions between the carboxyl end of the last amino acid and the ___________________ end of the next amino acid to be added to the growing chain.

a: amino	b: ionized	c: polypeptides
d: alpha-carbon	e: length	f: protein
g: carbon	h: noncovalent	i: R group
j: carboxyl	k: peptide bonds	l: side chains

m: hydroxide

indigofrog836

1. The level of protein structure that is stabilized primarilyby non-covalent interactions between the side chains within asingle polypeptide chain is refered to as its:

A) primary structure

B) secondary structure

C) tertiary structure

D) quaternary structure

E) none of the above

2. Collagen, a strong fibrous protein found in connectivetissue, bone, and the extracellular matrix, has a structure inwhich three left-handed helices wind around each other to form aright-handed triple helix. The primary structure of collagen has arepeat unit of -(Gly-X-Pro)- Which of the following bonds stabilizethe collagen triple helix? (mark all that apply)

A) Hydrogen bonds between hydroxyproline residues

B) Hydrogen bonds between N-H and C=O

C) Ionic bonds between amino acid side chains

D) Hydrogen bonds between charged amino acids

3. The non-covalent forces that stabilize the Beta-strandconformation of peptides include:

A) H-bonds between amide C=O and amide NH

B) Van der Waals packing between the peptide backbone atoms

C) Van der Waals packing due to side chain interdigitation

D) Only A and B above

E) None of the above

4. What is the approximate length difference of a 22-kDasingle-stranded ?-helical protein segment vs. a 22-kDasingle-stranded ?-strand protein segment? Assume a mean residuemass of 110 Da. Show work.

5. Circular dichroism measurements have shown that the peptidebackbone of poly-l-lysine (KKKKKKK) adopts a random coilconformation at pH 7.0, but becomes ?-helical as the pH is raisedabove 10. This observation is known as the

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BCEM 393 Lecture Notes - Lecture 2: Bovine Serum Albumin, Mercedes-Benz E-Class, Lysine

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